Crossfire is a way of improving frame rate in certain 3D games by splitting the 3D rendering across two video cards. To use it you need a Crossfire-capable motherboard with two PCI Express x16 slots, two identical video cards, and a power supply hefty enough to power your system with the extra video card installed.

Unless you've got gobs of money to spend on two top-of-the-line video cards, you're probably better off using a single more powerful card than two weaker ones in Crossfire.

Crossfire is not for beginners and (in my experience) you will have different issues with every game you play using it. Be it crashing, performance, visual errors, frame dips, etc; Crossfire can be a real headache.

Back when I first X'fired my 6870's I was playing BFBC2 religiously. In one driver release I was getting 100fps smoothly, beautifully, but would BSOD occasionally. The next, 40fps jittery, but never crashed. The next, 100fps, jittery, visual errors. Some games, I've never had issues. Some games, I've never even gotten Crossfire to work at all.

I don't know how SLI's compatibility compares to Crossfire, but I'm not too happy with my experience with ATI over the past few years.

In my previous gaming PC, I had two HD 4850s in crossfire. Seemed to work well at first mostly. Then about 2 years after the HD 4850 release, new AMD drivers made crossfire on my system no longer work in almost all games. Only 1 video card would show any GPU activity.

After searching around vainly for a fix and getting no help from AMD, I finally decided to risk flashing an HD 4850 bios from a different vendor than the card I owned. Crossfire started working again.

So yeah. Crossfire is basically an enthusiast option to use at your own risk. It may work well for the games you play for as long as you use your current video cards. It may very well not. Having a single GPU is a much safer bet, particularly if you're not the sort that enjoys tinkering around with your computer.

And even if Crossfire does work, as said above, you still run into potential issues with microstuttering and intermittent frame lags in some games. If you are an enthusiast that needs the fastest graphics subsystem around, then buying a couple of top of the line cards and crossfiring them is your only option. If your needs are more modest, I don't really recommend it.

Not only will the $200 cards probably have less memory, they will also have inferior performance for any app that doesn't support crossfire properly, and that is by far the larger category. I'm not even going to mention microstuttering in detail, but the short description is that a crossfire setup running at 60fps looks and feels more like 30fps due to unevenly timed frames. It's great for benchmark results but lousy in practical use.

If:

You have already bought the fastest single card money can buy

You have money to burn

You still want more performance

You have a power supply capable of running TWO of these cards

You have a compatible motherboard

The games you are playing benefit from crossfire

You don't give a damn about how hot, noisy or efficient your PC is

...then you might be satisfied with crossfire.

Some people ask me why I have always enclosed my signature in spoiler tags; There is a good reason for that, but I can't elaborate without giving away the plot twist.